1. Field of the Invention
The present invention relates to Digital Multimedia Broadcasting (DMB). More particularly, the present invention relates to a method and apparatus for synchronizing a broadcast channel between terminals, thus enabling several users to watch the same broadcast channel and enabling a corresponding terminal to monitor a broadcast channel that is being watched.
2. Description of the Related Art
With the convergence of mobile communications and broadcasting, Digital Multimedia Broadcasting (DMB) is attracting attention and is now being supported by a variety of terminals, such as a portable phone, a Personal Digital Assistant (PDA), a navigation unit, etc. DMB is a broadcasting service for modulating a variety of multimedia signals such as voice, image, etc. into digital signals for the reproduction thereof to a user. More particularly, DMB refers to a broadcasting service for enabling a user to view a diversity of multimedia broadcasting through a portable receiver or a vehicle receiver, etc.
With the advancement in memory technology, large amounts of digital multimedia data (e.g., moving picture data, music data, video data, etc.) are now able to be stored. In addition, with the increase in popularity of mobile communication terminals in recent years, a terminal (hereinafter, referred to as a ‘DMB phone’) that is able to receive DMB has been developed and commercialized. Accordingly, users can view DMB using the DMB phone without restrictions in their mobility. That is, the DMB phone has a feature of enabling the users to view DMB without regard to time/place.
More particularly, the use of DMB phones for viewing educational broadcasting using the DMB phones among juveniles, etc. is increasing. However, if the juveniles view DMB without restrictions, an undesired side effect may occur. For example, the juveniles may not have sufficient time management skills and therefore may end up viewing DMB when they should be engaged in other activities, or the juveniles may view adult programs that would have an undesirable influence on them, etc. To address this problem, Korean patent application Number 10-2006-0021778 entitled “METHOD AND APPARATUS FOR DIGITAL BROADCAST VIEW LIMIT” discloses a function of transmitting a history of DMB viewing, etc. from one terminal to another terminal and managing the viewing history, and a function of controlling a viewing right of a specific terminal in another terminal.
In a conventional technology, a viewing history can be managed in a text format or can be used for the purpose of controlling a viewing right. That is, if an authentication terminal restricts the viewing of a program and a viewing limit time, a DMB phone processes DMB data depending on the program restriction and the viewing limit time. However, the authentication terminal is not aware of what program the DMB phone is presently viewing. Thus, there is a problem that, if the authentication terminal does not add a restriction to viewing a program to a corresponding list beforehand, the juveniles may view the restricted program that is not yet listed in the corresponding list through the DMB phone.